https://gup.ugal.ro/ugaljournals/index.php/mtd <p style="margin: 0cm; margin-bottom: .0001pt;"><strong>DOI:</strong> <a href="https://doi.org/10.35219/mtd" target="_blank" rel="noopener">https://doi.org/10.35219/mtd</a></p> <p style="margin: 0cm; margin-bottom: .0001pt;">ISSN-L <span style="color: windowtext; text-decoration: none; text-underline: none;">2247-9635</span> ; ISSN <span style="color: windowtext; text-decoration: none; text-underline: none;">2247-9635</span></p> <p style="margin: 0cm; margin-bottom: .0001pt;"><strong>Frequency:</strong>&nbsp;quarterly</p> <p style="margin: 0cm; margin-bottom: .0001pt;"><strong>Subjects covered:</strong> testing and diagnosis of machine elements, materials and design solutions from the mechanical point of view</p> <p style="margin: 0cm; margin-bottom: .0001pt;"><strong>Contact:</strong>&nbsp;lorena.deleanu@ugal.ro</p> Galati University Press en-US Mechanical Testing and Diagnosis 2247-9635 <p>All rights are reserved for this publication, which is copyright according to the Romanian law of copyright. Excepting only any fair dealing for the purpose of the private study, research, review, comment and criticism, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, mechanical, electrical, electronic, optical, photocopying, recording or otherwise, without the prior express permission of the copyright owners.</p> https://gup.ugal.ro/ugaljournals/index.php/mtd/article/view/7069 <p style="text-align: justify;">This paper presents arguments in the favor of selecting the&nbsp;adequate set of filters λc (cut-off wavelength for roughness) and λs (sampling wavelength for eliminating noise), in studying the 3D&nbsp;amplitude parameters, including average arithmetic deviation of the&nbsp;surface (Sa), Ssk, Sku, Sq, Sv, Sp, St. This analysis was carried out&nbsp;for a surface of 1000 µm x1000 µm, from a ball made of chrome&nbsp;steel, with a diameter of 12.7 mm ± 0.0005 mm, which, according to&nbsp;the ISO standard 683-17:2023, they are finely grinded and have a&nbsp;high hardness (62...65 HRC) and a high quality surface. The authors&nbsp;present an analysis for 3D amplitude parameters, for the same&nbsp;surface, but after applying different pair of filtering (λs, λc) and&nbsp;discussed their influence on the values of amplitude parameters. For&nbsp;Sa, standard deviation of values obtained at the same λc, but for λs=0.8-250 µm, is decreasing to a lower value only for λc = 100-250 µm, but values increase from nanometers to higher average&nbsp;value (3.59 µm for λc=900 µm). Similar tendency was noticed for&nbsp;Sq. Ssk and Sku have revealed a convergence towards the largest&nbsp;value of λc, meaning that λs has no significant influence when the&nbsp;cut-off length is almost the dimension of the investigated area, at&nbsp;least for λs=0.8-250 µm. St decreases with the increasing of λs, but&nbsp;it increases with the increases of λc. A larger λs is favorable to avoid&nbsp;recording the deepest valley. It is important to report the λc and λs&nbsp;values as they have directly impact on roughness values (as&nbsp;demonstrate here for 3D amplitrude parameters, like Sa, Sq etc.).<br>This study and the cited references evidence that different settings&nbsp;can produce different results for the same surface. Including them in&nbsp;the report ensures transparency and reproducibility.</p> Lorena DELEANU Constantin GEORGESCU George Ghiocel OJOC Alexandru Viorel VASILIU George Catalin CRISTEA ##submission.copyrightStatement## 2024-01-20 2024-01-20 14 1 5 13